<div class="translate" id="isochron_intro"></div>

<p></p>
<translate class="legend"></translate>
<p></p>

<ol>
  <li>
    age  = x &plusmn; y 
    <span class="show4model1 hide4model2 hide4model3">
      (| z)
    </span>
    <p></p>
    <translate class="where"></translate>
    <p></p>
    <table>
      <tr>
	<td>x:</td>
	<td class="translate" id="isochron_t"></td>
      </tr>
      <tr>
	<td>y:</td>
	<td>
	  <translate class="err"></translate> 
	  <translate class="12sigmaci"></translate>.
	</td>
      </tr>
      <tr class="show4model1 hide4model2 hide4model3">
	<td>z:</td>
	<td><translate class="err_disp"></translate></td>
      </tr>
    </table>
  </li>
  
  <li>
    <span class="hidden show4PbPb">
      (<sup>207</sup>Pb/<sup>204</sup>Pb)<sub>c</sub></span>
    <span class="hidden show4ArAr">
      (<sup>40</sup>Ar/<sup>36</sup>Ar)<sub>0</sub></span>
    <span class="hidden show4UPby0option1">
      (Pb/Pb)<sub>c</sub>
    </span>
    <span class="hidden show4UPby0option2">
      (<sup>234</sup>U/<sup>238</sup>U)<sub>i</sub>
    </span>
    <span class="hidden show4UPby0option3">
      (<sup>230</sup>Th/<sup>238</sup>U)<sub>i</sub>
    </span>
    <span class="hidden show4ThUy0option1">
      (<sup>234</sup>U/<sup>238</sup>U)<sub>a</sub>
    </span>
    <span class="hidden show4ThUy0option2">
      (<sup>230</sup>Th/<sup>232</sup>Th)<sub>d</sub>
    </span>
    <span class="hidden show4ThU3 show4ThU4">
      (<sup>230</sup>Th/<sup>232</sup>Th)<sub>0</sub>
    </span>
    <span class="hidden show4ThUy0option3">
      (<sup>230</sup>Th/<sup>238</sup>U)<sub>a</sub>
    </span>
    <span class="hidden show4ThUy0option4">
      (<sup>234</sup>U/<sup>238</sup>U)<sub>i</sub>
    </span>
    <span class="hide4UPb hide4PbPb hide4ArAr hide4ThU">intercept</span>
    = x &plusmn; y 
    <span class="show4model1 hide4model2 hide4model3">
      <span class="hide4UPby0option2 hide4UPby0option3">
	(| z)
      </span>
    </span>
    <p></p>
    <translate class="where"></translate>
    <p></p>
    <table>
      <tr>
	<td>x:</td>
	<td class="translate" id="isochron_i"></td>
      </tr>
      <tr>
	<td>
	  y:
	</td>
	<td>
	  <translate class="err"></translate> 
	  <translate class="12sigmaci"></translate>.
	</td>
      </tr>
      <tr class="show4model1 hide4model2 hide4model3 hide4UPby0option2 hide4UPby0option3">
	<td>
	  <span class="hide4UPby0option2 hide4UPby0option3">z:</span>
	</td>
	<td>
	  <span class="hide4UPby0option2 hide4UPby0option3">
	    <translate class="err_disp"></translate>
	  </span>
	</td>
      </tr>
    </table>
  </li>

  <li class="show4model1 hide4model2 hide4model3">
    MSWD = x, p(&chi;<sup>2</sup>) = y 
    <p></p>
    <translate class="where"></translate>
    <p></p>
    <table>
      <tr>
	<td>x:</td>
	<td class="translate" id="isochron_mswd_x"></td>
      </tr>
      <tr>
	<td>
	  y:
	</td>
	<td class="translate" id="isochron_mswd_y"></td>
      </tr>
    </table>
  </li>

  <li class="hide4model1 hide4model2 show4model3">
    dispersion = x &plusmn; y
    <p></p>
    <translate class="where"></translate>
    <p></p>
    <table>
      <tr>
	<td>x:</td>
	<td class="translate hidden show4ThU1 show4ThU2",
	    id="isochron_omega_a"></td>
	<td class="translate show4UPb show4PbPb show4ArAr show4KCa 
		   show4RbSr show4SmNd show4ReOs show4LuHf show4UThHe 
		   hide4ThU1 hide4ThU2 show4ThU3 show4ThU4"
	    id="isochron_omega_b"></td>
      </tr>
      <tr>
	<td>y:</td>
	<td>
	  <translate class="err"></translate> 
	  <translate class="12sigmaci"></translate>.
	</td>
      </tr>
    </table>
  </li>

</ol>

<p></p>
<translate class="references"></translate>
<p></p>

<div class="hidden show4ThU1 show4ThU2">
  Ludwig, K.R. and Titterington, D.M., 1994.
  Calculation of 230Th/U isochrons, ages, and errors.
  <i>Geochimica et Cosmochimica Acta</i>,
  58(22), pp.5031-5042.
  <p></p>
</div>

<div class="hidden show4UPb">
  Ludwig, K.R., 1998. On the treatment of concordant uranium-lead ages.
  <i>Geochimica et Cosmochimica Acta</i>, 62, 665-676.
  <p></p>
</div>

Nicolaysen, L. Graphic interpretation of discordant age measurements
on metamorphic rocks, 1961. <i>Annals of the New York Academy of
Sciences</i>, 91(1):198–206.

<p></p>

<div class="hidden show4UPb">
  Vermeesch, P. 2020. Unifying the U-Pb and Th-Pb methods: joint
  isochron regression and common Pb correction, <i>Geochronology</i>,
  2(1), 119-131,
  <p></p>
</div>

<div class="hide4ThU1 hide4ThU2">
  York, D., Evensen, N.M., Martinez, M.L. and De Basabe Delgado, J., 2004.
  Unified equations for the slope, intercept, and standard errors of the
  best straight line. <i>American Journal of Physics</i>, 72(3), pp.367-375.
  <p></p>
</div>
